Immunohaematological Signatures of Malaria in Pregnancy: Comparative Leukocyte Distribution in Infected and Uninfected Pregnant Women in Owerri, Imo State, Nigeria

Abstract

Background: Malaria during pregnancy remains a major public health challenge in sub-Saharan Africa and is associated with maternal anemia, adverse fetal outcomes, and immune alterations. Changes in leukocyte distribution reflect host immune responses and may provide insight into immunohaematological patterns associated with malaria infection. Objective: The present study compared the differential leukocyte profiles among malaria-infected pregnant women (MP+), malaria-uninfected pregnant women (MP−), and non-pregnant women (controls) in Owerri, Imo State, Nigeria. Methods: A comparative cross-sectional study was conducted among 150 participants comprising 50 malaria-infected pregnant women, 50 malaria-uninfected pregnant women, and 50 apparently healthy non-pregnant women recruited through convenience sampling from selected health facilities in Owerri. Malaria infection was confirmed using Giemsa-stained thick and thin blood film microscopy. Complete blood counts and differential leukocyte parameters were determined using an automated hematology analyzer. Statistical analyses were performed using analysis of variance (ANOVA) and independent t-tests, with p < 0.05 considered statistically significant. Results: Malaria-infected pregnant women exhibited significantly lower lymphocyte percentages (22.70 ± 8.65%) compared with controls (41.12 ± 9.28%, p < 0.001), while the difference between MP+ and MP− groups (25.02 ± 7.11%) was not statistically significant (p = 0.146). Neutrophil percentages were significantly higher in both MP+ (73.46 ± 11.09%) and MP− (74.24 ± 7.69%) groups compared with controls (58.14 ± 9.51%, p < 0.001). Eosinophil percentages were significantly elevated in MP+ participants (1.94 ± 1.41%) relative to MP− (0.26 ± 0.44%) and controls (0.34 ± 0.48%) (p < 0.001). Monocyte and basophil levels showed no significant differences across groups. Conclusion: Malaria infection during pregnancy is associated with alterations in leukocyte distribution, particularly reduced lymphocyte and elevated eosinophil levels, while pregnancy itself appears associated with increased neutrophil proportions. These findings suggest that leukocyte profiles may reflect immunological responses to malaria infection in pregnancy. However, interpretation should be cautious due to the cross-sectional design, convenience sampling, and absence of formal sample size calculation, which may limit causal inference and generalizability.